Study on swelling of hydrogels (PAAm) at various temperatures by using fluorescence technique


Aktas D. , EVINGUER G. A. , PEKCAN O.

JOURNAL OF MATERIALS SCIENCE, cilt.42, sa.20, ss.8481-8488, 2007 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 42 Konu: 20
  • Basım Tarihi: 2007
  • Doi Numarası: 10.1007/s10853-007-1764-x
  • Dergi Adı: JOURNAL OF MATERIALS SCIENCE
  • Sayfa Sayıları: ss.8481-8488

Özet

Steady-state fluorescence (SSF) technique was employed for studying swelling of polyacrylamide (PAAm) hydrogels. Disc-shaped gels were prepared by free-radical crosslinking copolymerization of acrylamide (AAm) with N, N'- methylenebis (acrylamide) (BIS) as crosslinker in the presence of ammonium persulfate (APS) as an initiator. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine was measured during in situ swelling process at various temperatures and it was observed that fluorescence intensity values decreased as swelling is proceeded. Li-Tanaka equation was used to determine the swelling time constants, tau(c) and cooperative diffusion coefficients, D-c from intensity, weight and volume variations during the swelling processes. It is observed that swelling time constants, tau(c) decreased and diffusion coefficients, D-c increased as the swelling temperature is increased. The swelling activation energies, Delta E were measured from the intensity, weight and volume variations and found to be 10.7, 32.2 and 64.1 kJ mol(-1), respectively.